A gas turbine engine may be used to power various types of vehicles and systems. A particular type of gas turbine engine that may be used to power aircraft is a turbofan gas turbine engine. A turbofan gas turbine engine conventionally includes, for example, five major sections: a fan section, a compressor section, a combustor section, a turbine section, and an exhaust section. The fan section is typically positioned at the inlet section of the engine and includes a fan that induces air from the surrounding environment into the engine and accelerates a fraction of this air toward the compressor section. The remaining fraction of air induced into the fan section is accelerated into and through a bypass plenum and out the exhaust section.
The compressor section raises the pressure of the air it receives from the fan section, and the resulting compressed air then enters the combustor section, where a ring of fuel nozzles injects a steady stream of fuel into a combustion chamber formed between inner and outer liners. The fuel and air mixture is ignited to form combustion gases, which drive rotors in the turbine section for power extraction. In a typical configuration, the turbine section includes rows of stator vanes and rotor blades disposed in an alternating sequence along the axial length of a generally annular hot gas flow path. The rotor blades are mounted at the periphery of one or more rotor disks that are coupled to drive a main engine shaft. The gases then exit the engine at the exhaust section.
In most gas turbine engine applications, it is desirable to regulate the operating temperature of certain engine components in order to prevent overheating and potential mechanical failures attributable thereto. Most turbine components, particularly those exposed to the high temperatures of the mainstream gas flow, may benefit from temperature management. Accordingly, in many turbine sections, the volumetric space disposed radially inwardly or outwardly from the hot gas flow path includes internal cavities through which cooling air flow is provided. The cooling of the turbine components attempts to maintain temperatures that are suitable for material and stress level.
In many conventional engines, relatively high levels of cooling air flows have been used to obtain satisfactory temperature control of turbine components. However, it is generally desirable to employ mechanisms to minimize this cooling air since air from the compressor used for cooling is not available for combustion.
Accordingly, it is desirable to provide gas turbine engines with turbine sections having improved thermal management. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.